Posted 5/27/2016 3:31 PM (GMT -8)
Based on the most recently recommended reference range, 0.3 to 3.0 is "normal." Older recommendations set the range at 0.5 to 4.5; on this range your TSH would be a bit low, suggesting mild hyperthyroidism. If you also have symptoms, your doctor would likely want to lower your replacement hormone dose a bit.
TSH is a hormone that stimulates the thyroid to produce thyroxine. If your T4 is low, your TSH would usually be high because the pituitary gland is trying to kick-start the thyroid to increase production. Conversely, a low TSH is related to hyperthyroidism.